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Study on the Prearation and Physical Properties of Mn2NiAl Alloys

Author: ZhouZuoYing
Tutor: MengFanBin；LiuGuoDong
School: Hebei University of Technology
Course: Materials Physics and Chemistry
Keywords: Heusler alloys Semi-metallic Alloy structural Atomic placeholder Phase change
CLC: TG145
Type: Master's thesis
Year: 2011
Downloads: 27
Quote: 0
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Abstract


The Mn 2 NiGa found on the Hg 2 CuTi structure Heusler alloys with more attention. The alloy such Ferrimagnetism larger recoverable strain and magnetic enhancements strain, has peculiar magnetic variation, and the phase transition temperature near room temperature, and so have a good development space in the application domain. Preliminary study found also HG 2 CuTi Heusler structure alloy in Mn 2 the alloy NiGa approached people on Mn 2 NiAl alloy martensitic transformation, and at room temperature, the following may occur. The work of this thesis will focus on Mn 2 NiAl alloy preparation and physical properties. We have optimized the Mn 2 NiAl alloy annealing process samples after annealing at 960 ℃ and 970 ℃ atoms higher degree of order. We use the method of resistance strain gauge on the phase transition behavior of the alloy annealed at 960 ℃, alloy-17000ppm strain when cooled to 106K, and when the temperature rose to about 250K, alloy restored to its original strain value, indicating that the material is recoverable strain. Rejection with samples of different speeds, we measured their thermal magnetic curves, Mn 2 NiAl alloy degree of order to improve the lower the temperature, the material magnetic transition. Theoretically, we use first-principles calculations the barrier lattice parameters of the electronic structure of the material, found by the compression of the lattice parameters, the Mn 2 the NiAl alloy from the ferrimagnetic into metal. But it is worth noting that, the Mn 2 NiAl alloys are not satisfied with the usually semi-metallic alloys meet the Slater-Pauling rule. We successfully synthesized by arc melting stoichiometric 1:1:1:1 as Mn-Ni-Cr-Al Heusler alloy having a high degree of atomic order. The Cr incorporation of elements has greatly improved the Mn 2 NiAl alloy into a phase difficulties. 2 the NiAl alloy of Mn, Cr replace Mn is its electronic structure and magnetic study. We found different atom occupying the Mn-Ni-Cr-Al alloys exhibit different electronic structure of ferrous magnetic semi-metal, such as narrow-band semiconductor characteristics. We also synthesized a series of partial Mn-Ni-Al alloy and doping element of Co, Fe, Mn-Ni-Al alloy. Composition ratio of the alloy structure. Structure, magnetic properties and the phase transition properties of Mn-Ni-Cr-Sb alloy was studied experimentally. Material having excellent soft magnetic characteristics. The same time, we found that the material 125K near the martensitic transformation occurred in the vicinity of 170K reverse martensitic transformation hysteresis nearly 50K. First principle on CrMnNiZ (Z = Al, Ga, In, Si, Ge, Sn, Sb) series alloys was studied. First balanced by the lattice constant of the alloy is determined by geometry optimization, the variation of the lattice constant is mainly determined by the atomic size of the Z atoms. Analysis of the electronic density of states and band density map of the electronic structure and magnetic properties of the alloy.

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > Metallic materials > Manganese and its alloys
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